Gmail to Microsoft 365 Migration: Everything You Need to Know

Many organizations are making the move from Google Workspace (formerly G Suite) to Microsoft 365 to take advantage of Microsoft’s integrated productivity, collaboration, security, and compliance capabilities.

However, migrating email and collaboration data is not simply a matter of copying mailboxes. To ensure business continuity and a positive user experience, organizations need a well-planned migration strategy that accounts for mailbox data, calendars, contacts, permissions, and platform-specific limitations.

At Lumo365, we help organizations securely migrate from Gmail to Microsoft 365 Exchange Online using proven migration technologies and industry best practices, delivering a seamless transition with minimal downtime.

Why Organizations Are Moving to Microsoft 365

Microsoft 365 provides a unified platform for:

• Exchange Online for enterprise email
• Microsoft Teams for collaboration
• OneDrive for Business for personal file storage
• SharePoint Online for document management
• Microsoft Entra ID for identity management
• Microsoft Defender security services
• Microsoft Purview compliance and data governance

For many organizations, consolidating email, collaboration, file storage, security, and compliance into a single platform simplifies IT administration and improves productivity.

What Is a Gmail to Microsoft 365 Migration?

A Gmail to Microsoft 365 migration involves moving user mailboxes from Google Workspace Gmail to Microsoft Exchange Online. Depending on project requirements, migrations may also include calendars, contacts, and other supported mailbox data. Exchange Online supports specialized migration processes for organizations transitioning from Google Workspace to Microsoft 365.

What Data Can Be Migrated?

Using migration platforms, organizations can migrate the following Gmail content to Microsoft 365.

Email Messages

The following mailbox content is typically migrated:

• Inbox
• Sent Items
• Drafts
• Archived Mail
• Custom folders and labels
• Email attachments
• Read and unread status
• Mailbox structure

This allows users to continue working with familiar mailbox content after moving to Exchange Online.

Gmail Labels and Folders

Google Workspace uses labels rather than traditional folders. During migration, labels are converted into Outlook folders to preserve mailbox organization.

Migrated items include:

• Folder hierarchy
• Labels
• Custom mailbox organization

Contacts

Personal contacts and address book information can be migrated into Microsoft 365 Contacts.

Migrated contact information typically includes:

• Names
• Email addresses
• Phone numbers
• Contact details

Calendars

Google Calendar data can be migrated to Microsoft 365 calendars, including calendar events and meeting information.

Migrated items include:

• Calendar appointments
• Recurring meetings
• Calendar entries
• Google Hangouts links within meetings where applicable

Additional Supported Items

The following supported items:

• Muted emails (migrated as regular email)
• Google Categories (Social, Promotions, Updates, Forums)
• Calendar notifications

What Does NOT Migrate?

A successful project requires understanding platform limitations before migration begins.

The following items are generally not migrated or require manual recreation:

Google Chat

The following items are not included in mailbox migrations:

• Google Chat conversations
• Google Chat attachments
• Chat history

These services do not directly map to Exchange Online mailboxes.

Google Spaces

Microsoft 365 does not provide a direct migration target for:

• Google Spaces
• Spaces conversations
• Spaces permissions

Google Groups

Google Groups content is not included in standard mailbox migrations. Organizations should review business requirements for Google Groups before migration planning.

Calendar Permissions

Although calendar items migrate, calendar sharing permissions and delegate access typically require manual configuration after migration. Shared calendars may behave differently because Google Workspace supports multiple owners for a calendar.

Automatic Replies

Out-of-office and automatic reply settings must typically be recreated after migration.

Client-Side Rules

The following generally require recreation in Microsoft Outlook or Exchange Online:

• Gmail filters
• Client-side rules
• Personal mailbox automation settings

Google Drive Linked Attachments

Email messages containing Google Drive links migrate, but the linked Google Drive content does not move as part of a mailbox migration. File migrations should be handled separately through a Google Drive to OneDrive migration project.

Post-Migration Changes

The migration tool, not a synchronization platform. Changes made in Gmail after migration are not automatically synchronized to Microsoft 365.

Important Technical Considerations

Before beginning migration, organizations should understand several technical considerations.

Gmail Labels Become Outlook Folders

Because Gmail uses labels rather than folders, migrated messages may appear differently in Outlook.

Messages with multiple labels may appear in multiple folders after migration.

Contact Groups

Google Contact Groups migrate differently than Outlook contact folders.

Contacts in Contact Groups migrate to the top-level Contacts folder. Folders may be created for groups, but contacts are not automatically sorted into those folders.

Shared Calendars

Google calendars can have multiple owners. Shared calendars may migrate to users who have “Make changes and manage sharing” permissions, depending on the source configuration.

Authentication & Access Requirements

Migration projects typically require:

• Google Workspace administrative access
• Google API configuration
• Service account permissions
• Microsoft 365 administrative permissions
• Exchange Online mailbox provisioning

Large Mailboxes

Organizations with large mailboxes often benefit from staged migration approaches that move historical data before final cut-over. We recommends pre-stage migration passes as part of migration preparation.

How Lumo365 Delivers a Zero-Stress Migration

Our fully managed migration service includes:

• Migration planning and assessment
• Google Workspace analysis
• Microsoft 365 tenant preparation
• Gmail mailbox migration
• Calendar and contact migration
• User communication and coordination
• Cut-over management
• Post-migration support
• End-user assistance

Through our structured migration methodology, organizations experience:

• Minimal downtime
• Secure cloud-to-cloud migration
• Preserved mailbox organization
• Reduced project risk
• Expert project management
• Faster user adoption

Ready to Move from Gmail to Microsoft 365?